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Commit a39d1f3f authored by Cyrill Gorcunov's avatar Cyrill Gorcunov Committed by Ingo Molnar
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x86, x2apic: Track the x2apic cluster sibling map 



In the case of x2apic cluster mode, we can group IPI register
writes based on the cluster group instead of individual per-cpu
destination messages.

For this purpose, track the cpu's that belong to the same x2apic
cluster.

Signed-off-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Cc: steiner@sgi.com
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20110519234637.421800999@sbsiddha-MOBL3.sc.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a27d0b5e

arch/x86/kernel/apic/x2apic_cluster.c

+70 −2
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <asm/ipi.h>



static DEFINE_PER_CPU(u32, x86_cpu_to_logical_apicid);

static DEFINE_PER_CPU(cpumask_var_t, cpus_in_cluster);



static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)

{
@@ -48,6 +49,11 @@ static void 
	native_x2apic_icr_write(cfg, apicid);

}



static inline u32 x2apic_cluster(int cpu)

{

	return per_cpu(x86_cpu_to_logical_apicid, cpu) >> 16;

}



/*

 * for now, we send the IPI's one by one in the cpumask.

 * TBD: Based on the cpu mask, we can send the IPI's to the cluster group
@@ -162,15 +168,77 @@ static void x2apic_send_IPI_self(int vector) 
}



static void init_x2apic_ldr(void)

{

	unsigned int this_cpu = smp_processor_id();

	unsigned int cpu;



	per_cpu(x86_cpu_to_logical_apicid, this_cpu) = apic_read(APIC_LDR);



	__cpu_set(this_cpu, per_cpu(cpus_in_cluster, this_cpu));

	for_each_online_cpu(cpu) {

		if (x2apic_cluster(this_cpu) != x2apic_cluster(cpu))

			continue;

		__cpu_set(this_cpu, per_cpu(cpus_in_cluster, cpu));

		__cpu_set(cpu, per_cpu(cpus_in_cluster, this_cpu));

	}

}



 /*

  * At CPU state changes, update the x2apic cluster sibling info.

  */

static int __cpuinit

update_clusterinfo(struct notifier_block *nfb, unsigned long action, void *hcpu)

{

	unsigned int this_cpu = (unsigned long)hcpu;

	unsigned int cpu;

	int err = 0;



	switch (action) {

	case CPU_UP_PREPARE:

		if (!zalloc_cpumask_var(&per_cpu(cpus_in_cluster, this_cpu),

					GFP_KERNEL)) {

			err = -ENOMEM;

		}

		break;

	case CPU_UP_CANCELED:

	case CPU_UP_CANCELED_FROZEN:

	case CPU_DEAD:

		for_each_online_cpu(cpu) {

			if (x2apic_cluster(this_cpu) != x2apic_cluster(cpu))

				continue;

			__cpu_clear(this_cpu, per_cpu(cpus_in_cluster, cpu));

			__cpu_clear(cpu, per_cpu(cpus_in_cluster, this_cpu));

		}

		free_cpumask_var(per_cpu(cpus_in_cluster, this_cpu));

		break;

	}



	return notifier_from_errno(err);

}



static struct notifier_block __refdata x2apic_cpu_notifier = {

	.notifier_call = update_clusterinfo,

};



static int x2apic_init_cpu_notifier(void)

{

	int cpu = smp_processor_id();



	per_cpu(x86_cpu_to_logical_apicid, cpu) = apic_read(APIC_LDR);

	zalloc_cpumask_var(&per_cpu(cpus_in_cluster, cpu), GFP_KERNEL);



	BUG_ON(!per_cpu(cpus_in_cluster, cpu));



	__cpu_set(cpu, per_cpu(cpus_in_cluster, cpu));

	register_hotcpu_notifier(&x2apic_cpu_notifier);

	return 1;

}



static int x2apic_cluster_probe(void)

{

	return x2apic_mode;

	if (x2apic_mode)

		return x2apic_init_cpu_notifier();

	else

		return 0;

}



struct apic apic_x2apic_cluster = {